Apparatus for adjusting electrical contacts



June 19, 1956 M. SIMON ET AL 2,750,982

APPARATUS FOR ADJUSTING ELECTRICAL CONTACTS Filed March 3, 1952 2Sheets-Sheet l I l --J i !1\ l A! n 22\ 18 'm U I] -4} I} A 10a 36 /9 15 3 1: 111 2 4 48 40 I 1 g //a g9 I '1 G 46 7 42 29 45 44 4/ 32 2 A 2630 3/34 Inventors qndwem 6mm 1 r- 1 :36 M. SIMON ETAL June 19.

APPARATUS FOR ADJUSTING ELECTRICAL CONTACTS Filed March 5, 1952 2SheetsSheet 2 United States Patent APPARATUS FOR ADJUSTING ELECTRICALCONTACTS Malcolm Simon and Frederick Emil Rommel, London,

England, assignors to Telephone Manufacturing Company Limited, London,England, a British company Application March 3, 1952, Serial No. 274,544

Claims priority, application Great Britain March 9, 1951 13 Claims. (Cl.15348) This invention relates to electrical contacts and moreparticularly to arrangements for adjusting multiple spring contact setsof the cantilever type.

The inventionhas for its object to provide an improved method of andmeans for adjusting electrical contact springs, and thereby the contactscarried by them and in accordance with the invention a contact spring ofthe cantilever type is adjusted by bending the spring past its elasticlimit in one direction, then bending it past its elastic limit in theopposite direction and continuing such bending process in alternatedirections with decreasing amplitude until the elastic limit is nolonger exceeded.

The setting up, by manual adjustment, of multiple contact spring sets,such as those employed in electromagnetic relays for telecommunicationand like services, is a lengthy, tedious and expensive procedure whichcontributes largely to the manufacturing cost of the relay. In anapplication of Frederick Emil Rommel, Ser. No. 198,061, filed November29, 1950, now Patent No. 2,630,500, granted March 3, 1953, there isdescribed a construction of relay in which the number of adjustmentsrequired to set up the multiple spring set employed is less than inconventional relay constructions; the construction is such that thefixed springs can be adjusted before the moving springs are inserted,the adjustment required being only that necessary to space the contactsaccurately, that is, within a small working tolerance, from each otherand from a datum surface.

The present invention is concerned more particularly with a method ofand a machine for adjusting the fixed contacts of a relay described inthat prior specification, but as will appear hereinafter a machine inaccordance with the invention can be used generally where it is requiredto adjust a series of cantilever springs so as to space them accuratelywith respect to each other and, if required, to a datum surface.

The invention will be better understood, and further features of theinvention will appear from the following description of one embodimentof the invention, as applied to a machine for adjusting the fixedcontact springs of a relay of the type described in the Rommel patent,in conjunction with the accompanying drawings in which:

Figure 1 is a side elevation, with part of the drive gears removed, ofthe contact setting machine;

Figure 2 is a section through the same machine taken on the line 22 ofFigure l; in this figure the line 1-1 shows the plane of the view onwhich Figure 1 is taken;

Figure 3 is a side elevation, showing the side opposite that shown inFigure 1;

Figure 4 is a front elevation, on an enlarged scale, of the settingplate, and

Figure 5 is a cross-section of the setting plate on the line 55 ofFigure 4.

Very briefly this machine comprises a main, robust framework 10, ofroughly rectangular shape, at one end of which is a frame 11 whichreciprocates in a vertical plane; this frame carries a setting plate 12which receives the tips of the contact springs 13 of the spring set 14of ICC the relay, which is located accurately on the framework. Theframe is reciprocated by a mechanism which causes the amplitude of thereciprocations to be gradually and successively decreased, and themechanism permits of adjustment of the initial, maximum amplitude, andalso the mean position of the frame. The mechanism is operated from handor power driven shafts, and the operation is automatic and cyclic, sothat in one cycle of adjustment the amplitude of reciprocation isinitially a maximum, then decreases slowly to zero, and returns rapidlyto maximum, on continued rotation of the shaft.

Describing now the machine in more detail, the framework 10 has at itsupper part an accurately machined surface 10a on which the relaystructure can be precisely located by stops 15 and clamped by clamps 16with the fixed contact springs in a position which is approximately overone end face of the framework. As appears from the description of thisspring set in the Rommel patent, the spring set forms a separate unit,having surfaces which can be used as datum surfaces for adjustment ofthe springs. Accordingly, these surfaces are located with reference tothe stops 15 and the datum surfaces 100, either by directly engagingthese surfaces or with interposed gauge blocks 17.

At the forward end of the framework 10 is the reciprocating frame 11.This frame consists of two vertical parallel side members 11a and 11bsecured rigidly together by cross members 18, and is carried from theframework by means of two pairs of parallel links 19 pivoted to theframe at 20 and to the side members at 21. The links are themselvescoupled together by cross members 22; the rear of these members passthrough holes 10b in the frame.

At its upper part the frame 11 has secured to it, preferably detachably,the setting plate 12. This setting plate has in it a series ofaccurately finished openings which are intended to receive respectivelythe tips of the contact springs. The plate is made by milling grooves12a and 12b at right angies in opposite faces of a rectangular steelplate, the openings being formed where the grooves intersect, soproviding a pattern of rectangular openings as shown in Figure 4. Thegrooves 12b on the one face are made quite shallow, whilst the grooves12a on the other face are substantially wider and deeper. This leavesample room for movement of the spring contacts.

The mechanism for reciprocating the frame includes a main driving shaft25 mounted horizontally in the framework and which is provided with ahandle at 26, or is adapted to be power driven. This driving shaftpasses through the framework 10 and at its inner end carries a crankmember 27, and in addition the shaft is coupled to drive a rotary snailcam 24 at a substantially reduced speed, in this particular constructionat a speed of one forty-third of that of the driving shaft 25. With thisobject there is secured to the shaft 25 a pinion 28 which meshes with apinion 29 on a shaft 30, mounted in the framework 10; pinion 29 drivespinion 31 on the same shaft 30, and this pinion 31 in turn drives pinion32 on shaft 25. Pinion 32 likewise moves with a further pinion 33 on thesame shaft and this pinion 33 drives the final pinion 34 on shaft 30,and thereby to drive that shaft. The snail cam is fast on the shaft 30,and is accordingly driven thereby.

The crank member 27 on the shaft 25 is used to cause the oscillation ofa forked arm 35, this being effected by securing the forked arm on asupporting shaft 36, this shaft also having secured to it a drive lever37. A con necting link 38 is then attached at its one end to the crankmember 27' and at its other to the drive lever 37, as shown in Figure 3.The attachment of the link to'th'e drive lever is by a pivot pin 39,which is mounted in a slot 370: in the lever 37 so that its positionalong the slot can be varied. As the crank rotates, the drive lever andhence the arm shaft is oscillated; the extent of the oscillation can bevaried by movement of the pin in the slot; the mean position of the armshaft can be varied by adjusting the shaft angularly with respect to thedrive lever. For this purpose the drive lever is adjustably secured tothe shaft, by a split clamp 37b.

In this way the fork on the arm is oscillated; this oscillation iscommunicated to one of the links l? by which the frame is carried,thereby to oscillate the frame. This is effected by means of a pivotedcoupling let er as; this coupling lever 4t} is pivoted near its one by apivot pin 41 mounted in the frame iii, and at its opposite end carries apin 42 which engages a slot in the link by which the frame is mounted.The coupling lever is slotted at 46a and the motion of the fork istransmitted to the coupling lever and hence to the frame by means of astud 43 which enters the fork and also passes through the slot.

As thus far described, the

. Clltt,

fork 35 drives the stud E3, the stud drives the coupling lever 49, andthe coupling lever drives the liik and thus the frame ill. The extent ofthe resultant movement of the frame depends inter alia on the distancebetween the centre of the shaft 36 carrying the fork 35 and the centreof the stud 43, if the stud is at the end of the fork the motion will bea maximum, and if the stud is coaxial with the shaft there will be nomotion at all. The amplitude of the frame is controlled by movement ofthe stud in this way, the stud being secured at the end of a support rod44 the other end of which is pivoted at 45 in a slide plate 46. Theslide plate is guided for linear movement by guide slots 46a thereinengaging guide pins 47 on the framework it) of the machine, and carriesa cam-follower roller 4% engaging the edge of the snail cam 24. Theslide plate is tensioned by spring 49 to keep the follower on the cam.

This arrangement produces the effect that on rotation of the drivingshaft the fork is oscillated as described above; at the same time thecam 24 is rotated slowly moving the slide plate 46 and with it thesupport rod 44 and the stud 413. The movement transmitted to the link 19and to the frame 11 is thus slowly decreased, until the stud reaches apoint on or near the axis of the shaft 36, when the frame ceases tooscillate. If the driving shaft 25 continues to rotate the cam followerfalls down the steep return part of the cam 24 to bring the parts backto their initial position, as shown in Figure 1.

As a result of this motion the contact springs 13 are bent backwardlyand forwardly with decreasing amplitude, and are finally accuratelylocated with respect to each other and to a predetermined surface on therelay assembly. The backwards and forwards movement of the springs canalso be used to improve somewhat the mechanical properties of thecontact springs. The mechanical bending cause a work hardening of thespring, if the metal thereof has not previously been fully hardened, andthere is a progressive hardening along the length of the spring with thesuccessive bending movements. For this reason it is preferred that themetal of the springs is not fully hardened. Satisfactory results havebeen obtained using Phosphor bronze strip sold as hard, and having ahardness in the range of 185 to 210 as measured by a Vickers pyramiddiamond hardness test, to British standard specification N0. 427.

We claim:

1. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine in spaced relation in a column and relative to a datumposition, means comprising a frame with spaced slots in which the endsof said springs are individually engaged, said frame being movable inalternate directions to bend the same through desired set positions withreference to said datum position, a driving member, a variablemechanical transmission means coupling said driving member to saidspring engaging means to move the same in alternate directions to bendthe springs repeatedly through their desired set positions bydisplacements of decreasing amplitude in the successive movements.

2. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine in spaced relation in a column and relative to a datumposition, means comprising a frame with spaced slots in which the endsof said springs are individually engaged, said frame being movable inalternate directions to bend the same through desired set positions withreference to said datum position, a drivin member adapted to be drivenat a uniform rate, a variable mechanical transmission means couplingsaid driving member to said spring engaging means to move the same inalternate directions to bend the springs repeatedly through theirdesired set positions by displacements of decreasing amplitude in thesuccessive movements.

3. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine relative to a datum position, means engaging said springsand movable in alternate directions to bend the same through desired setpositions with reference to said datum position, a driving memberadapted to be driven at a uniform rate, a member driven from saiddriving member and (mused to pivot about an axis, a coupling memberengageable with said pivoted member at a variable distance from saidaxis, and cam means operated by said driving member for varying thedistance of said coupling member from the axis of said pivoted member,whereby the movement of said coupling member is progressively varied,and means for moving said spring engaging means in accordance with themovement of said coupling means, thereby to bend the springs repeatedlythrough their desired set positions by displacements of decreasingamplitude in the successive movements.

4. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine relative to a datum position, means engaging said springsand movable in alternate directions to bend the same through desired setpositions with reference to said datum position, a driving memberadapted to be driven at a uniform rate, a member pivotable about an axisand driven from said driving member, a member coupling said drivingmeans to said spring engaging means and engageable with said pivotedmember, said pivoted member having guide surfaces thereon between whichsaid coupling member is constrained to move at a variable distance fromsaid axis, cam means operated by said driving member for decreasing thedistance of said coupling member from the axis of said pivoted memberwhereby the range of movement of said coupling member is progressivelydecreased, and means for moving said spring engaging means in accordancewith the movement of said coupling member, thereby to bend the springsrepeatedly through their desired set positions by displacements ofdecreasing amplitude in the successive movements.

5. A machine for simultaneously adjusting a plurality of electricalcontact springs. comprising mounting means for mounting said springs onsaid machine relative to a datum position, means engaging said springsand movable in alternate directions to bend the same through the desiredset positions with reference to said datum position, a driving memberadapted to be driven at a uniform rate, a member pivotable about an axisand driven from said driving member, a member coupling said drivingmeans to said spring engaging means and engagea le with said pivotedmember, said pivoted member having guide surfaces thereon between whichsaid coupling member is constrained to move at a variable distance fromsaid axis, cam means operated by said driving member for decreasing thedistance of said coupling member from the axis of said pivoted memberwhereby the range of movement of said coupling member is progressivelyreduced, and means for moving said spring engaging means in accordancewith the movement of said coupling means, thereby to bend the springsrepeatedly through their desired set positions by displacements ofdecreasing amplitude in the successive movements.

6. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine relative to a datum position, means engaging said springsand movable in alternate directions to bend the same through desired setpositions with reference to said datum position, a driving memberadapted to be driven at a uniform rate, a member pivotable about an axisand driven from said driving member, said pivoted member having a slottherein, a member coupling said driving means to said spring engagingmeans, a stud carried by said coupling member and engaged in said slotof said pivoted member for constraining said coupling member to move ata variable distance from said axis, cam means operated by said drivingmember for decreasing the distance of said coupling member from the axisof said pivoted member whereby the range of movement of said couplingmember is progressively decreased, and means for moving said engagingmeans in accordance with the movement of said coupling means thereby tobend the springs repeatedly through their desired set positions bydisplacements of decreasing amplitude in the successive movements.

7. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine relative to a datum position, means engaging said springsand movable in alternate directions to bend the same through desired setpositions with reference to said datum position, a driving memberadapted to be driven at a uniform rate, a slotted member pivotable aboutan axis and driven from said driving member, an arm carrying a studwhich extends through the slot of said pivoted member, a slide plate onwhich said arm is pivoted, cam means operated by said driving member formoving said slide plate to decrease the distance of said stud from theaxis of said pivoted member, whereby the range of movement of said studis progressively decreased, and means coupling said stud to said springengaging means, thereby to actuate said spring engaging means to bendthe springs repeatedly through their desired set positions bydisplacements of decreasing amplitude in the successive movements.

8. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising mounting means for mounting said springs onsaid machine relative to a datum position, means engaging said springsand movable in alternate directions to bend the same through desired setpositions with reference to said datum position, a driving memberadapted to be driven at a uniform rate, a slotted member pivotable aboutan. axis and driven from said driving member, an arm carrying a studwhich extends through the slot of said pivoted member, a slide plate onwhich said arm is pivoted, a snail cam operated by said driving memberfor moving said slide plate progressively to decrease the distance ofsaid stud from the axis of said pivoted member, whereby the range ofmovement of said stud is progressively decreased, and means couplingsaid stud to said spring engaging means, thereby to actuate said springengaging means to bend the springs repeatedly through their desired setpositions by displacements of decreasing amplitude in the successivemovements.

9. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising a stationary framework, means for mountingsaid springs on said stationary framework in predetermined relation to adatum position, means engaging said springs and movable in alternatedirections to bend the same through desired set positions with referenceto said datum position, said spring engaging means including a platehaving therein apertures to receive said springs, a driving memberadapted to be driven at a uniform rate, a slotted member pivotable aboutan axis and driven from said driving member, an arm carrying a studwhich extends through the slot of said pivoted member, a slide plate onwhich said arm is pivoted, a snail cam operated by said driving memberfor moving said slide plate progressively to decrease the dis tance ofsaid stud from the axis of said pivoted member, whereby the range ofmovement of said stud is progressively decreased, and means couplingsaid stud to said spring engaging means, thereby to actuate said springengaging means to bend the springs repeatedly through their desired setpositions by displacements of decreasing amplitude in the successivemovements.

10. A machine as recited in claim 9, wherein said spring engaging meanscomprises a frame carrying a plate apertured to receive said springs andmeans mounting said frame on said stationary framework for oscillation.

11. A machine as recited in claim 9. wherein said spring engaging meanscomprises a frame carrying a plate apertured to receive said springs,links pivoted on said stationary framework and supporting said frame foroscillation.

12. A machine as recited in claim 9, wherein said snail cam, afterprogressively moving said slide plate to decrease the range of movementof said stud to a minimum is reset by said driving means, in combinationwith spring means for returning said slide plate to space said stud at amaximum distance from the axis of said pivoted member.

13. A machine for simultaneously adjusting a plurality of electricalcontact springs comprising a stationary framework, means for mountingsaid springs on said stationary framework in predetermined positionsrelative to a datum position, means for engaging said springs andmovable in alternate directions to bend the same through desired setpositions with reference to said datum position, said spring engagingmeans comprising a plate grooved at the opposite sides thereof toprovide apertures to receive said springs, a driving member adapted tobe driven at a uniform rate, a slotted member pivotable about an axisand driven from said driving member, an arm carrying a stud whichextends through the slot of said pivoted member, a slide plate on whichsaid arm is pivoted, a snail cam operated by said driving member formoving said slide plate progressively to decrease the distance of saidstud from the axis of said pivoted member, whereby the range of movementof said stud is progressively decreased, and means coupling said stud tosaid spring engaging means thereby to actuate said spring engaging meansto bend the springs repeatedly through their desired set positions bydisplacements of decreasing amplitude in the successive movements.

References Cited in the file of this patent UNITED STATES PATENTS1,336,543 Stull Apr. 13, 1920 2,251,967 Yoder Aug. 12, 1941 2,389,885Anderson Nov. 27, 1945 2,609,858 Engel Sept. 9, 1952 FOREIGN PATENTS611,949 Great Britain Nov. 5, 1948

